关键词: 
角动量 /
核耗散 /
裂变截面 /
随机模型

摘要: 核耗散降低了裂变截面值(σ_drop^f )。基于Langevin 模型，研究了角动量对σ_drop^f 作为鞍点前摩擦强度β 函数的影响。发现在低自旋，摩擦对σ_drop^f的影响显著增强。通过考察系统195Bi，201Bi 和207Bi 的σ_drop^f 随β 的演化，发现摩擦效应随着Bi 核中质比(N/Z) 的增加而变大。这些结果建议，为了更好地在实验上用裂变截面探测β，应产生那些具有低自旋、高N/Z 的热核系统。Using the Langevin model, we study the effect of angular momentum on the drop of fission cross sections caused by friction over its standard statistical-model value, σ_drop^f as a function of presaddle friction strength β. It is found that friction effects on σ_drop^f are substantially enhanced at low spin. In addition, by investigating the evolution of σ_drop^f with β for 195Bi, 201Bi and 207Bi nuclei, we find that friction effects become greater with increasing the neutron-to-proton ratio (N/Z) of Bi nucleus. These results suggest that on the experimental side, to precisely probe presaddle dissipation by measuring fission excitation functions, it is best to yield excited nuclear systems with a small spin and a large N/Z.